Sarnat Grading Scale of HIE

To the right is Alissa, the founder’s daughter, several days after birth. She suffered severe HIE and is being tapped with a respritary cup to help to clear secretions from her lungs. Also note the NG or Nasal Gastric Tube used for feeding. Her low tone did not allow her body to control saliva from entering and accumlating in her lungs. Also notice the cap on her head, she was kept warm from her birth. Modern treament is to place HIE infants into a cold state to slow down the metabulism and help prevent what is know as the “Cascade of Neurologic Injury” that occurs in the first 48-72 hours after birth.

Dr. Sarnat

The clinical characteristics of HIE (Hypoxic-Ischemic Encephalopathy) can be described as mild, moderate, or severe. The most common grading or staging system is by the Sarnat scale developed by Sarnat and Sarnat in 1976.

The Sarnat Score combines clinical and EEG findings (I, II, III = mild, moderate, severe). When using only clinical findings, this grading system is called the Modified Sarnat Score. The different stages are detailed below.

Mild HIE – Sarnat Stage I

Hyper-alert

Eyes wide open

Does not sleep

Irritable

No seizures

Usually lasts < 24 hours

Moderate HIE – Sarnat Stage II

Lethargy (difficult to rouse)

Reduced tone of the extremities and/or trunk

Diminished brainstem reflexes (pupil/gag/suck)

Possible clinical seizures

Severe HIE – Sarnat Stage III

Coma (cannot be roused)

Weak or absent respiratory drive

No response to stimuli (may have spinal reflex to painful stimuli)

Flaccid tone of the extremities and trunk (floppy)

Diminished or absent brain stem reflexes (pupil/gag/suck)

Diminished tendon reflexes

EEG severely abnormal (suppressed or flat EEG with or without seizures)